(m+n)2=52

⇒m2+n2+2mn=25

⇒m2+n2=25−2mn=25−2.6=25−12=13

⇒m3+n3=(m+n)(m2+n2−mn)=5.(13−6)=35

Ans : 35.

\(\left(m+n\right)^2=5^2\)

\(\Rightarrow m^2+n^2+2mn=25\)

\(\Rightarrow m^2+n^2=25-2mn=25-2.6=25-12=13\)

\(\Rightarrow m^3+n^3=\left(m+n\right)\left(m^2+n^2-mn\right)=5.\left(13-6\right)=35\)

Ans : 35.